It'd Be Crazy Easy for Brazil to Block the Web Right Now

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It'd Be Crazy Easy for Brazil to Block the Web Right Now

As the Olympics unfold in Brazil this week, the digital rights group AccessNow started a petition to make sure the government there doesn’t turn off the Internet.

But that’s not a thing Brazil could do, right? And even if it were possible, it wouldn’t, right?

Wrong. It could shut down the entire Internet, or just block certain sites, as it has done repeatedly. On June 19 a Brazilian judge ordered Internet providers to block access to What’sApp in an attempt to force the company to reveal personal user data for a criminal investigation. It was the third time in seven months that Brazilians lost access to the extremely popular encrypted messaging platform, which boasts more than 100 million users across the country.

Now, with the entire world watching and more than 500,000 visitors in Rio de Janeiro for the Olympics, it’s unlikely Brazilian authorities will try to censor the Internet during the games. But, it could. Easily. That’s because Internet infrastructure is remarkably malleable. If a government does order censorship, in only a few seconds an Internet provider can block any point on their network from sending or receiving information, whether targeting a single website or the entire Internet.

Here’s how easy it would be.

Blocking Websites

The old adage that the Internet routes around censorship is more of an ideal than a reality.

ISPs link the edges of their networks together using routers that speak to each other via a “border gateway protocol” that tells other ISPs where to send packets of data. They’re basically just tables of routing information. One Internet provider's router might advertise that it’s only three hops from the final destination of where another ISP is trying to send data, and if that’s the most efficient route, that’s the route the data will take.

“The easiest way for an Internet service provider to block access to a website is to update their routing tables to say 'Don’t forward along any data marked for delivery to the blocked IP address,” says Jeremy Gillula, a technologist at the Electronic Frontier Foundation. “The data just goes nowhere.”

That’s how it was likely done in Brazil. It’s also probably what happened in Turkey when social media was blocked during the recent coup attempt. So if a country wanted to block Facebook, the ISP would just list all of Facebook’s IP addresses and mark them as destinations to not deliver to in the border gateway protocol.

Another way to sever traffic to a certain destination is by a process called domain name poisoning. “Anytime you go to Facebook.com, it passes through an Internet provider’s domain name server that translates the URL into an Internet IP address,” says Mason Carroll, a network engineer at Monkeybrains.net, a California-based ISP. “So you could delete Facebook.com from the DNS server and if someone tries to go that website, they’ll just get nothing back.” Alternatively, an Internet provider can route Facebook.com to a different IP address.

Blocking the Whole Net

Interfering with routing protocols can also be used to shut the Internet down entirely. In Egypt in 2011, then-president Hosni Mubarak ordered all the ISPs to black out the Internet during the revolution. “The Internet providers essentially started advertising nothing to the rest of the Internet via their border gateway protocol,” says Gillula. “And they were basically saying, ‘We don’t exist anymore. If you’re trying to reach Egyptian servers we don’t know how to get to them.’ And as a result Egypt basically dropped off the face of the Internet.”

Fearing protests, the government in Kashmir, India ordered a mobile Internet blackout last month after authorities killed a famous political dissident. And the government of the Republic of Congo shut off the Internet entirely for a few days in April during elections to prevent “illegal reporting” of ballot numbers. In May, the Iraqi government blacked out the Internet to keep sixth graders from cheating on national exams. Algeria did the same in December of last year to prevent students from cheating.

“The Brazilian Supreme Court’s reversal does make it less likely that another judge will try to block websites again anytime soon,” says Carlos Affonso Souza, Director of the Institute for Technology and Society, a Rio de Janeiro-based digital rights nonprofit.

While Olympic tourists in Rio have so far been able to surf the web unfettered, three times in seven months is a dismal track record. Brazilian judges seem to consider Internet censorship a tool in their arsenal, and the Supreme Court reversal isn’t a final decision, says Affonso Souza. So it’s probably smart for visitors to go ahead and download theTor browser and a VPN app, two tools that circumvent common methods of Internet censorship, just in case.